Patients who undergo hemodialysis or other procedures that remove fluid and waste products from the blood often die of cardiac complications. Many possible factors may contribute to such death, including stress placed on the heart due to the increased fluid volume in these patients. Increased fluid volumes and innate inability to remove waste products from the blood, in some cases, can also contribute to electrolyte and pH imbalance that can affect cardiac contractility and efficiency. Further, rapid changes in fluid volume or pH or electrolyte concentration of the blood during hemodialysis or other fluid removal processes may place additional stress on the heart and may contribute to the high rate of morbidity for patients who undergo blood fluid removal procedures.
Patients who undergo blood fluid removal procedures, such as hemodialysis, typically have a number of cardiovascular parameters such as blood pressure, heart rate or heart rhythm parameters that are outside of general population norms. For example, Secemsky et al., have shown that a patient population undergoing chronic hemodialysis had a prevalence of abnormal heart rate variability of 82%, a prevalence of abnormal heart rate turbulence of 75%, and a prevalence of T-wave alternans of 96%, which are all indicators of heightened probability of sudden cardiac death (Heart Rhythm, vol. 8, no. 4, pp. 592-598, April 2011).
Typically, chronic hemodialysis patients undergo periodic examinations that allow a healthcare provider to set various parameters of the blood fluid removal procedures, such as the profile of fluid removal, the composition of dialysate or replacement fluid employed, and the like. With current standards of care, these examinations occur about once a month, absent any pressing health issues with the patient. However, hemodialysis or similar procedures may occur three to four times a week. Thus, the patient may undergo 10 to 15 or more blood fluid removal sessions before the prescription or parameters are changed. It is possible, for example, that a prescription with regard to dialysate or replacement fluid composition will not be appropriate for a patient several days or weeks after the prescription is set. Accordingly, it may be desirable to more frequently determine whether the blood fluid removal prescription is appropriate. In addition, it may be desirable to adjust parameters during a blood fluid removal session in a manner that may improve patient health and reduce morbidity.